210 likes | 366 Views
Scientific Advisory Committee (SAC) Sub-Committee on Stock Asssessment (SCSA) Working Group on Demersal Species Izmir, Turkey, 15-19 September, 2008. Stock assessment of hake in GSAs 15 and 16. F. Fiorentino, M. Dimeck, M.T. Spedicato, A. Abella, P. Accadia, V. Gancitano.
E N D
Scientific Advisory Committee (SAC)Sub-Committee on Stock Asssessment (SCSA)Working Group on Demersal SpeciesIzmir, Turkey, 15-19 September, 2008 Stock assessment of hake in GSAs 15 and 16 F. Fiorentino, M. Dimeck, M.T. Spedicato, A. Abella, P. Accadia, V. Gancitano
The aim of this paper is: • To compare assessments of hake done with different approaches and data deriving from indirect (fisheries monitoring) and direct (scientific surveys) sources in the investigated area; • To evaluate the use of different biological reference points in order to recommend fishery advices.
An attempt of VPA under steady state assumptions with landings information of 2006 and 2007 in GSA 16 by winVIT package
Catch and fishing mortality by size of hake (F & M) Mean Yield and LDF of landings of 2006 and 2007 _GSA 16 by winVIT Package and scalar M
Current status Y/R and SSB/R analysis vs Factor of current fishing mortality of hake (F & M) with winVIT Package.
Diagnosis from winVIT package…….. …overfishing…
Y/R and SSB/R analysis vs Factor of current fishing mortalityof hake (F & M) with Yield Package. GSA 15 & 16
Diagnosis from Yield package…….. Main BRPs obtained by Yield package for hake in GSA 15 & 16
What is the current exploitation of hake? According to the Y/R and trawl surveys mortalities … the stock is ….overfished……… and to reach a target such as F0.1….. the reduction of current F should be of about 60%
Other analythical approaches… The recostruction of hake landings fin the GSA 16 by ALADYM Model………..
Some management scenarios for GSA 16 based on ALADYM model…………..
What about the stock status according to “global” approaches? Equilibrium composite biomass dynamic models Electronic sheet by A. Abella
Non equilibrium biomass dynamic models Electronic sheet by A. Abella